On TQ-Algebras

A topological algebra A is called a Q-algebra if its set of quasi-invertible elements (of invertible elements, if A is unital) is an open set. This class of topological algebras has been extensively studied by several authors, but mostly in unital or commutative case. Properties of (not necessarily unital or commutative) TQ-algebras and, in the special case, of TQ-algebras with functional topological spectrum are given in the present paper.